The use of microstructures in printable media is well known. Most such arrangements utilize reflective microstructures to provide an image, pattern, or color that changes with the angle at which the media is viewed. The microstructures in question generally function by diffraction, interference, scattering, diffusion, transmission or reflection of light of a preselected wavelength or by polarizing reflected light. Other methods and structures for producing an optically discernable image, pattern, or color using microstructures are also known.
Generally, images, colors, or patterns are produced by directly applying or depositing microstructures onto the media in a desired arrangement prior to the use of the media, i.e. the images, colors, or patterns are printed on the media. Secondary images, colors, or patterns may be applied to the media over the pre-existing microstructural images, patterns, or colors. In other cases molding, stamping, patterning, pressure embossing, or mechanical abrasion of selected areas are used to produce the optical patterns. In recent times, high power lasers have also been used to ablate, melt, or otherwise damage the microstructures on the media to form a secondary image. In short, the formation of images on media using microstructures is relatively expensive, requires complicated and dangerous lasers, and/or may damage or chemically decompose the media being printed. Accordingly, there is a need for a media and a method of printing using microstructures that is inexpensive, flexible, and which uses apparatuses that are safe and which do not damage the media being printed.
It is therefore an object of the present invention to provide media having a substrate that may be readily modified using relatively low power light source sources. It is another object of the invention to provide media for printing having microstructural features that may be readily modified to form an image without damaging the substrate of the media. One other object of the present invention involves the provision of a printing apparatus that utilizes a relatively low power light/radiation source to form an image on media in such a way as to avoid damaging or chemically decomposing the media.
These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.